MVVM 中的实时 UI 和 LiveCharts 更新

Question

I'm trying to implement a real-time plot UI, i'm using WPF with the MVVM Pattern and Live-Charts by beto-rodriguez as my plot library, but i have some trouble with updating the graphs in real time. I know that i have to run multiple threads to update the UI in realtime, but every single way i tried doesn't work (i'm learning C# now). I'm confused of how i should properly implement this pattern for the realtime update, and if the plot library is able to do that.

This is my actual code (its a simplified version of what i will do and doesn't implement any multithread code)

ModelView Code:

using System;
using System.ComponentModel;
using System.Windows;
using LiveCharts;


    namespace TestMotionDetection
    {
        class MainViewModel : INotifyPropertyChanged
        {
            public SeriesCollection Series { get; set; }

            public Func<double, string> YFormatter { get; set; }
            public Func<double, string> XFormatter { get; set; }

            public DataViewModel SData
            {
                set
                {
                    Series[0].Values.Add(value);
                    OnPropertyChanged("Series");
                }
            }

            public event PropertyChangedEventHandler PropertyChanged;

            public MainViewModel()
            {
                SeriesConfiguration<DataViewModel> config = new SeriesConfiguration<DataViewModel>();
                config.Y(model => model.Value);
                config.X(model => model.Time);

                Series = new SeriesCollection(config)
                {
                    new LineSeries {Values = new ChartValues<DataViewModel>(), PointRadius = 0}
                };

                XFormatter = val => Math.Round(val) + " ms";
                YFormatter = val => Math.Round(val) + " °";
            }

            protected virtual void OnPropertyChanged(string propertyName)
            {
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
            }

            public void generateData()
            {
                DataViewModel val = new DataViewModel();
                for (int i = 0; i < 500; i++)
                {
                    val.Time = i;
                    val.Value = i + 2.3f;
                    SData = val;
                }
            }
        }
    }

Here is the View code:

using System.Windows;


namespace TestMotionDetection
{
    /// <summary>
    /// Logica di interazione per MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        private MainViewModel vista;

        public MainWindow()
        {
            vista = new MainViewModel();
            DataContext = vista;
        }

        private void button_Click(object sender, RoutedEventArgs e)
        {
            vista.generateData();
        }
    }
}

And the XALM:

<Window x:Class="TestMotionDetection.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:lvc="clr-namespace:LiveCharts;assembly=LiveCharts"
        Title="Example 2  (WPF)"
        Width="1025.213"
        Height="482.801">

    <Grid>
        <lvc:LineChart Margin="0,2,245,-2"
                       LegendLocation="Right"
                       Series="{Binding Series}">
            <lvc:LineChart.AxisX>
                <lvc:Axis LabelFormatter="{Binding XFormatter}" Separator="{x:Static lvc:DefaultAxes.CleanSeparator}" />
            </lvc:LineChart.AxisX>
            <lvc:LineChart.AxisY>
                <lvc:Axis LabelFormatter="{Binding YFormatter}" />
            </lvc:LineChart.AxisY>
        </lvc:LineChart>
        <Button x:Name="button"
                Width="151"
                Height="79"
                Margin="804,47,0,0"
                HorizontalAlignment="Left"
                VerticalAlignment="Top"
                Click="button_Click"
                Content="Button" />
    </Grid>
</Window>

[UPDATE 1] [ ] 1

Answer 1

Your XFormatter & YFormatter should both be like this:

private Func<double, string> _yFormatter;
public Func<double, string> YFormatter { 
    get{ return _yFormatter; }
    set
    {
        _yFormatter = value;
        OnPropertyChanged("YFormatter");
    }

If you are using C#6 you should do nameof(YFormatter) instead.

That will cause the view to update, otherwise the view has no way of knowing that the formatter changed.